Propeller



F. MILLER Aug. 4, 1942.

PROPELLER 2 Sheets-Sheet 1 Filed June 4, 1941 gvwcwvtm Fra 210/6 M 17/82;

F. MILLER PRQPELLER Aug. 4, 1942.

Filed June 4, 1941 2 Sheets-Sheet 2 Franc/15 jYf/lez Patented Aug. 4, 1942 UNITED STATES PATENT OFFICE PROPELLEB Francis Miller, Bockville, Conn. Application June 4, 1941, Serial No. 396,612

. 2 Claims. My invention relates to propellers and more particularly to variable pitch propellers for model airplanes and the like.

One of the principal objects of my invention is to provide a variable pitch propeller which is automatically controllable in a manner to main-' A further object of my invention is to provide a propeller construction equipped with means responsive to propeller thrust or pull for varying the pitch of the blades.

An important object of my invention is to provide a device of the character described which is simple in construction, durable in use,,efliclent in operation and economical in manufacture.

Other objects and advantages will be apparent from the following description, appended claims and annexed drawings.

Referring to the drawings wherein like reference character's designate like parts throughout the several views:

Figure 1 is a side elevation of a propeller constructed in accordance with my invention.

Figure 2 is a front elevation of the propeller.

Figure 3 is a detail sectional view taken on the line 3-3 of Figure 2.

Figure 4 is a vertical sectional view taken on the line 4-4 of Figure 3.

Figure 5 is a detail sectional view taken on the line 8-! of Figure 3. v

Figure 6 is a perspective view of the inner end of one of the blades. 7

Figure 7 is a perspective view of the cam.

In practising my invention, as illustrated in the drawings. I provide a cylindriform propeller hub housing 5 having front and rear walls I and I respectively with the rear wall constituting a detachable plate for permitting access to the interior of the housing. The front and rear walls 8 and I are formed with centrally disposed openings through which slidably extends elongated sleeve l of a cam 9, the latter being formed with a collar ll between the ends of the sleeve I. The

collar I0 is fashioned with a pair of oppositely arranged cam slots II and with the walls defining said slots being disposed in abaxial relation with the axis of the sleeve 8.

The housing I is formed with a pair of oppositely disposed radially extending bearings II in which are rotatably mounted sleeves ll having closed inner walls ll. The sleeves II have blades IL mounted therein and fixed thereto, by means of transverse pins ii, the inner ends ofpropeller The inner ends of the propeller blades receive the outer ends of-pins H; the latter extending through the end walls H of the sleeves l3 and terminate within the cam' slots Ii. The inner peripheral wall I8 of the housing 5, between the pins i1, is formed with a pair of oppositely disposed longitudinal grooves I! each receiving a pair of ball bearings 28 rotatably carried within pairs of oppositely disposed seats 2| formed in the collar II. The ball bearings permit relative axial movement of the housin and cam and preclude relative rotation therebetween. a

The sleeve I is fixed about the end of a drive or propeller shaft 22, the latter terminating an appreciable distance postjacent the front end of the sleeve 8. The front end section of the sleeve 8 is interiorly threaded and accommodates therein the threaded shank 23 of a retainer 24, the latter being provided with head 25 abutting the front end of the sleeve 8 and with said head being of a materially greater diameter than the diameter of the sleeve 3. Mounted upon the sleeve 8, between the front wall 6 and head 25, is a coil spring 26 normally urging the housing 5 in a direction away from the head 25.

In operation, it being understood that the blades are rotated about the axis of the shaft 22 through the ball bearing connection between the cam and housing, acceleration or deceleration of the shaft results in a variation of the thrust or pull of the blades thereby causing the housing to move axially with respect to the cam thus efiecting rotative adjustment of the blades with respect to the housing due to the sliding engagement of the pin H with the walls of the cam slots ii. Obviously, rotative adjustment of the blades with respect to the housing serves to vary the pitch of the blades dependent upon the speed of the shaft 22. From the foregoing, it will be obvious that my invention lends itself to a ready incorporation within model airplanes and tune-- tions in a manner to automatically vary the pitch of the propeller blades in accordance with the speed of the propeller shaft.

Without further elaboration the foregoing will so fully explain the invention that others may, by applying current knowledge, readily adapt the same for use under various conditions of service. Moreover, it is not indispensable that all the features of the invention be used conjointly since they may be employed advantageously in various combinations and sub-combinations.

It is obvious that the invention is not confined to the herein described use therefor as it may be utilized for any purpose to which it is adaptable. It is therefore to be understood that the invention is not limited to the specific construction as illustrated and described as the same is only illustrative of the principles of operation, which are capable of extended application in various forms, and that the invention comprehends all construction within the scope of the appended claims.

What I claim is:

1. A device of the character described, comprising, a propeller shaft, a sleeve mounted on said shaft and fixed to the latter for rotation therewith, said sleeve provided with a collar having ball seats and formedwith a pair of oppositely disposed cam slots extending abaxially with respect to the axis of the shaft, a hub housing .slidably mounted on said sleeve and formed with radially extending bearings, propeller blades having inner ends rotatably mounted in said bearlugs and serving to axially move said housing in one direction with respect to said shaft, said inner ends provided with pins extending into of the hub, and a tension spring imposed between said grooves and'coacting with the walls defining said grooves to effect rotative adjustment of said propeller blades upon said axial movement, the

by said blades.

inner peripheral face of said housing provided with longitudinal extending grooves, balls disposed in said seats and extending into. said grooves for efiectlng rotation of said housing with said sleeve and to permit axial movement of said housing with respect to said sleeve, and means carried by said sleeve and engaging said housing for moving the latter on said sleeve in a direction opposite from said first mentioned direction.

2. In a propeller, a hub having a bore provided with oppositely arranged grooves, a power driv-' en sleeve extending into said bore and having op.- positely arranged seats, elements engaging said seats and grooves to stablisha rotary drive between the hub and sleeve and-to permit said hub to slide endwise of the sleeve, propeller blades r0- tatably mounted in the hub and tending to impart axial movement of the hub on the sleeve in one'direction, a collar fixed on said sleeve and having oppositely arranged cam grooves therein, rigid pins fixed to the blades and fitting in the cam grooves, a, retainer element threaded in the sleeve and including a head arranged exterlorly sist said axial movement of the hub on the sleeve FRANCIS 

